1. Technical Field
The invention disclosed broadly relates to power circuits and more particularly relates to SCR power circuits.
2. Background Art
Switching a silicon controlled rectifier (SCR) in high power applications requires precise control of the SCR's current to insure proper timing of the device turn-on. Large systems operating from a power line frequently have reactive and electronic loads that cause distortion of the current and voltage waveforms. Polarity reversals of the load current due to this distortion cause undesirable mid-cycle commutation or turn-off of the SCR.
Isolation and control of an SCR has frequently been accomplished in the prior art with a transformer to couple energy between the SCR gate and its controller. Individual drive transformers required for each SCR gate increases the complexity of this prior art driver circuit approach. Transformer gate drivers add significant size and weight to a design and cannot sustain a continuous DC drive signal. The need to resupply gate signals at a high pulse rate places severe performance limits on prior art transformer designs for SCR drive systems.